Absolute magnetostrictive displacement measuring magnetic tape

Abstract

The present invention discloses an absolute magnetostrictive displacement measuring magnetic tape. Magnetic scales are embedded in through-holes in a slot layer according to a certain coding rule and fixed between a steel wire layer and a coating layer. During use, the magnetic tape is suspended vertically and maintained vertically by tension provided by a spring at the bottom. A magnetostrictive displacement sensor is mounted on a measured object and can always sense the magnetic scales in the tape. The coding rule for the magnetic scales ensures that the spacing between any set of interleaved magnetic scales is no greater than the measurement range of the magnetostrictive sensor, ensuring that at least two magnetic scales are always sensed. Furthermore, the coding rule ensures that any set of adjacent magnetic scales are inconsistent. Therefore, the absolute position of the first magnetic scale sensed can be determined by combining the time interval between pulses excited by the magnetic scales on the displacement sensor with the speed of sound to convert the spacing between adjacent magnetic scales. Combined with the transit time of the first pulse signal in the magnetic scale, the absolute position of the object secured by the magnetostrictive displacement sensor can be measured in real time.

Description

Technical Field

[0001] The present invention relates to an absolute magnetostrictive displacement measuring magnetic tape, in particular to a magnetostrictive displacement measuring magnetic tape used for detecting the absolute running position of a moving part. Background Art

[0002] An absolute magnetostrictive linear ruler is an ultra-long-range absolute position measurement system used in applications such as elevators and autonomous vehicles. It primarily consists of a magnetostrictive displacement sensor and a magnetic encoding system. The magnetostrictive displacement sensor detects the positional information in the magnetic encoding system in real time as the object in question moves, enabling precise absolute positioning. Absolute magnetostrictive displacement measurement tape is a form of magnetic encoding system with the following characteristics:

[0003] 1) The distance between any two magnetic scales in the absolute magnetostrictive displacement measurement tape is different;

[0004] 2) The distance between any two sets of inter-phase magnetic scales in the absolute magnetostrictive displacement measurement tape shall not be greater than the effective range of the magnetostrictive displacement sensor;

[0005] 3) During operation, a certain gap will be maintained between the absolute magnetostrictive displacement measuring tape and the magnetostrictive displacement sensor.

[0006] Absolute magnetostrictive displacement measurement tape, used in conjunction with magnetostrictive displacement sensors, is a first in the field of ultra-long-range measurement. A similar technology currently exists, magnetic scale technology. Patent number CN114538225A, "A Magnetic Scale Elevator Position Identification System," discloses an elevator car positioning system based on a magnetic scale. The magnetic scale's tape is continuously encoded, requiring very high tolerances for the width and spacing of the magnetic scales, making the manufacturing process more complex and costly. The magnetic scale's tape is made of soft magnetic rubber and can be easily broken even with a steel backing. The magnetized magnetic field strength is also susceptible to interference from external magnetic fields and gradually weakens over time. Summary of the Invention

[0007] The invention provides an absolute magnetostrictive displacement measuring magnetic tape, which is suitable for an absolute magnetostrictive linear ruler to realize absolute position measurement and can be used for a long time after being installed once.

[0008] The present invention can be achieved through the following technical solutions:

[0009] An absolute magnetostrictive displacement measuring magnetic tape comprises a top mounting structure, a magnetic tape body, and a bottom mounting structure; the top mounting structure includes a top fixing plate and rivets, the rivets securing the magnetic tape body to prevent it from falling out of the mounting holes of the top fixing plate; the bottom mounting structure includes a bottom connecting plate, a spring, and a bottom fixing plate connected in sequence, the magnetic tape body being secured to the bottom connecting plate; the magnetic tape body comprises a steel wire layer, a slot layer, a magnetic scale, and a coating layer, the steel wire layer being made of a group of parallel steel wires wrapped in a flexible material; the slot layer being disposed on the steel wire layer and uniformly provided with through holes, the magnetic scale being secured within the through holes.

[0010] Furthermore, the magnetic tape body and the bottom connecting plate are fixed by rivets.

[0011] Furthermore, the width of the through holes in the slot layer is smaller than the distance between adjacent through holes.

[0012] Furthermore, the steel wire layer, groove layer and coating layer are flexible strips, and the types of materials thereof include but are not limited to rubber and polyurethane.

[0013] Furthermore, the through holes of the magnetic mark and the slot layer are in the shape of a circle, a rectangle or a square.

[0014] Furthermore, the steel wire layer, the groove layer and the coating layer are fixed by coupling agent bonding or hot melt bonding.

[0015] Furthermore, the magnetic marker is made of a permanent magnet and cooperates with the sensor to excite the ultrasonic guided wave signal.

[0016] Furthermore, a magnetostrictive displacement sensor is mounted on the object being measured and can always sense the magnetic scales in the magnetic tape. The magnetic scale arrangement scheme is as follows: Assuming that the spacing between adjacent through-holes is L and the effective measurement range of the magnetostrictive displacement sensor is M, a small distance between magnetic scales will affect measurement accuracy. Therefore, a minimum spacing requirement is imposed between magnetic scales. Assuming that the minimum spacing between magnetic scales is N, the through-holes where odd-numbered magnetic scales are located are numbered P(2n-1)=(G+1)*(n-1)+1, where n=1, 2, 3, ...; and the through-holes where even-numbered magnetic scales are located are numbered P(2n)=(G+3)*(n-1)+1+X, where n=1, 2, 3, ...; X is related to the number of through-holes with the smallest magnetic scale spacing, and G is related to the number of through-holes with the largest magnetic scale spacing. The function int() is used to get the integer part; if G is an odd number, the value of G is subtracted by 1; the maximum value of n

[0017] In the present invention, magnetic markers are embedded in through-holes in the slot layer according to a specific coding rule and fixed between a steel wire layer and a coating layer. The steel wire layer ensures the tensile strength of the magnetic tape, while the coating layer protects the magnetic markers and prevents them from falling off. During use, the magnetic tape is suspended vertically and maintained vertically by a spring at the bottom. The magnetostrictive displacement sensor is mounted on the object being measured and can always sense the magnetic markers in the tape. The coding rule for the magnetic markers ensures that the spacing between any set of interleaved magnetic markers does not exceed the measurement range of the magnetostrictive sensor, ensuring that at least two magnetic markers are always sensed. Furthermore, the coding rule ensures that any set of adjacent magnetic markers is inconsistent. Therefore, the absolute position of the first magnetic marker sensed can be determined by combining the time interval between the pulses excited by the magnetic markers on the displacement sensor with the speed of sound to convert the spacing between adjacent magnetic markers. Combined with the transit time of the first pulse signal from the magnetic marker, the absolute position of the object to which the magnetostrictive displacement sensor is attached can be measured in real time.

[0018] The beneficial effects of the present invention are:

[0019] The magnetic scale arrangement of the present invention ensures that the magnetostrictive displacement sensor covers at least two magnetic scales during motion, maximizes the effective measurement range of the magnetostrictive displacement sensor, increases the sparseness of the magnetic scale arrangement to reduce costs, and ensures that the spacing between any two adjacent magnetic scales is different. By identifying the component distances of the magnetic scales and combining them with the transit time of the pulse signal corresponding to the first magnetic scale, the absolute position of the object to which the magnetostrictive displacement sensor is attached can be measured. If implemented, this invention can provide real-time and accurate absolute position information input for motion control of industrial equipment such as elevator cars and autonomous vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an overall schematic diagram of the present invention.

[0021] Figure 2 It is a schematic diagram of the top installation structure of the present invention.

[0022] Figure 3 It is a schematic diagram of the bottom installation structure of the present invention.

[0023] Figure 4 It is a schematic diagram of the magnetic tape structure of the present invention.

[0024] Figure 5 It is a distribution diagram of the magnetic tape slot structure of the present invention.

[0025] Figure 6 It is a schematic diagram of the assembly of the magnetic tape and the sensor of the present invention.

[0026] Figure 7 Graph 2 is a signal diagram measured in the embodiment.

[0027] In the picture:

[0028] 1. Top mounting structure, 2. Magnetic tape body, 3. Bottom mounting structure, 4. Top fixing plate, 5. Rivet, 6. Bottom connecting plate, 7. Spring, 8. Bottom fixing plate, 9. Steel wire layer, 10. Slot layer, 11. Magnetic scale, 12. Coating layer, 13. Through-hole width, 14. Distance between adjacent through-holes, 15. Magnetostrictive displacement sensor, 16. First pulse transit time, 17. Interval between the first group of pulses. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] like Figure 1 As shown in FIG, an absolute magnetostrictive displacement measuring magnetic tape of the present invention comprises a top mounting structure 1, a magnetic tape body 2 and a bottom mounting structure 3. Figure 2 The top mounting structure 1 is shown, which includes a top fixing plate 4 and rivets 5. The rivets 5 are used to fix the tape body 2 to prevent the tape body 2 from falling off from the mounting hole of the top fixing plate 4. Figure 3 The bottom mounting structure 3 is shown, which includes a bottom connecting plate 6, a spring 7 and a bottom fixing plate 8. The tape body 2 and the bottom connecting plate 6 are also fixed with rivets. The function of the spring 7 is to provide a certain degree of tension to ensure the vertical installation of the tape body 2. Figure 4 The figure shows the magnetic tape body 2, which includes a steel wire layer 9, a groove layer 10, a magnetic mark 11 and a coating layer 12. The steel wire layer 9 is made of a group of parallel steel wires wrapped with a flexible material, and its main function is to ensure the tensile strength of the magnetic tape body 2; uniformly distributed through holes are provided in the groove layer 10, and its main function is to fix the magnetic mark 11 and ensure the spacing between adjacent magnetic marks; the magnetic mark 11 is made of a permanent magnet material and cooperates with the sensor to excite the ultrasonic guided wave signal; the coating layer 12 is a flexible strip, and its main function is to prevent the magnetic mark 11 from falling off or being damaged.

[0031] like Figure 5 As shown, the through holes in the slot layer 10 are evenly distributed, and the through hole width 13 is smaller than the distance 14 between adjacent through holes;

[0032] The steel wire layer 9, the groove layer 10 and the coating layer 12 are flexible strips, and the types of materials thereof include but are not limited to rubber and polyurethane.

[0033] The through holes of the magnetic mark 11 and the slot layer 10 may be in the shape of a circle, a rectangle or a square.

[0034] The steel wire layer 9, the groove layer 10 and the coating layer 12 are fixed by coupling agent bonding or hot melt bonding.

[0035] The magnetic scale arrangement scheme is as follows:

[0036] Assume that the spacing 14 between adjacent through-holes is L, and the effective measurement range of the magnetostrictive displacement sensor 15 is M. If the distance between magnetic scales is too small, the measurement accuracy will be affected. Therefore, a minimum spacing requirement is imposed between magnetic scales, assuming that the minimum spacing between magnetic scales is N. The through-holes where the odd-numbered magnetic scales reside are numbered P(2n-1)=(G+1)*(n-1)+1, where n=1, 2, 3, ...; the through-holes where the even-numbered magnetic scales reside are numbered P(2n)=(G+3)*(n-1)+1+X, where n=1, 2, 3, ...; X is related to the number of through-holes with the minimum magnetic scale spacing, and G is related to the number of through-holes with the maximum magnetic scale spacing. The function int() is used to get the integer part; if G is an odd number, the value of G is subtracted by 1; the maximum value of n

[0037] like Figure 5 As shown, assuming that the magnetic scale 11 and the through-holes in the slot layer 10 are rectangular, and the through-hole width 13 is 8 mm, the distance 14 between adjacent through-holes can be set to 12 mm (i.e., L = 12 mm); assuming that the effective measurement range of the magnetostrictive displacement sensor 15 is 2000 mm (i.e., M = 2000 mm). The minimum distance between the magnetic scales is 100 mm (i.e., N = 100 mm);

[0038] From this we can calculate, Since 163 is an odd number, the value of G is subtracted by 1, that is, G=162, the maximum value of n Therefore, a tape can contain at most 2*n max = 148 magnetic marks, and the position of each magnetic mark can be determined by combining the above formula for the through-hole numbering of the magnetic mark, as shown in Table 1.

[0039] Table 1 Magnetic scale layout distribution table

[0040] Magnetic scale number 1 2 3 4 5 … 147 148 Through hole number 1 10 164 175 327 … 11900 12055

[0041] Table 1 means that magnetic marker No. 1 is set at through-hole No. 1, magnetic marker No. 2 is set at through-hole No. 10, and so on. The spacing distribution between adjacent magnetic markers can also be calculated, as shown in Table 2.

[0042] Table 2 Distribution of adjacent magnetic scale spacing

[0043]

[0044]

[0045] Table 2 indicates that the distance between magnetic markers 1 and 2 is 9 through-holes, the distance between magnetic markers 2 and 3 is 154 through-holes, and so on. As can be seen from Table 2, the minimum number of through-holes required for magnetic marker spacing is 9, which translates to a magnetic marker spacing of 9*12=108mm, which is greater than 100mm, meeting the minimum magnetic marker spacing requirement.

[0046] The magnetic scale spacing can be divided into two categories, one is odd-number increasing (9, 11, 13, ...), and the other is even-number decreasing (154, 152, ...). Therefore, the spacing between any two sets of adjacent magnetic scales is different. In addition, the number of through-holes between the magnetic scale spacing of any two sets of interlaced magnetic scales is 163 or 165 (for example, the number of through-holes between the spacing between magnetic scales No. 1 and No. 3 is 163, and the number of through-holes between magnetic scales No. 2 and No. 4 is 165). The maximum interlaced magnetic scale spacing can be obtained as 165*12=1980mm<2000mm, which meets the requirement that the magnetostrictive displacement sensor 15 always covers at least 2 magnetic scales during movement, such as Figure 6 shown.

[0047] Before the actual measurement, the sensor will learn all the adjacent magnetic scale intervals on the tape and determine the absolute position of the first magnetic scale in each interval. During the measurement process, the typical signals detected by the sensor are as follows: Figure 7 As shown, the magnetic scale spacing corresponding to the first pulse group can be converted based on the first pulse interval 17 combined with the sound velocity, thereby determining the absolute position of the magnetic scale corresponding to the first pulse. The absolute position of the sensor zero point can be determined by combining the distance information converted from the first pulse transit time 16.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An absolute magnetostrictive displacement measuring magnetic tape, characterized in that: It comprises a top mounting structure (1), a magnetic tape body (2) and a bottom mounting structure (3); The top mounting structure (1) comprises a top fixing plate (4) and a rivet (5), wherein the rivet (5) fixes the tape body (2) to prevent the tape body (2) from falling off from the mounting hole of the top fixing plate (4); The bottom mounting structure (3) comprises a bottom connecting plate (6), a spring (7) and a bottom fixing plate (8) connected in sequence, and the magnetic tape body (2) is fixed to the bottom connecting plate (6); The magnetic tape body (2) comprises a steel wire layer (9), a slot layer (10), a magnetic mark (11) and a coating layer (12), wherein the steel wire layer (9) is made of a group of parallel steel wires wrapped with a flexible material; the slot layer (10) is arranged on the steel wire layer (9) and is evenly provided with through holes, and the magnetic mark (11) is fixed in the through holes; The magnetic tape body (2) and the bottom connecting plate (6) are connected and fixed by rivets; The magnetic marker (11) is made of a permanent magnet and cooperates with the sensor to excite the ultrasonic guided wave signal; The magnetostrictive displacement sensor is installed on the object to be measured and can sense the magnetic mark in the tape at all times. The magnetic scale arrangement scheme is as follows: Assuming that the distance between adjacent through holes (14) is L , the effective measuring range of the magnetostrictive displacement sensor (15) is M , assuming the minimum magnetic scale spacing is N , Set the through-hole numbers where the odd-numbered magnetic markers are located to: The through-hole numbers where the even-numbered magnetic marks are located are: ; X is related to the number of through-holes with the minimum magnetic scale spacing, and G is related to the number of through-holes with the maximum magnetic scale spacing. ， The function of int() is to get the integer part; if If is an odd number, Subtract 1 from the value of The maximum value 。 2. The absolute magnetostrictive displacement measuring magnetic tape according to claim 1, characterized in that: The through hole width (13) in the groove layer (10) is smaller than the distance (14) between adjacent through holes.

3. The absolute magnetostrictive displacement measuring magnetic tape according to claim 1, characterized in that: The steel wire layer (9), groove layer (10) and coating layer (12) are flexible strips, and the types of materials thereof include but are not limited to rubber and polyurethane.

4. The absolute magnetostrictive displacement measuring magnetic tape according to claim 1, characterized in that: The through-holes of the magnetic mark (11) and the slot layer (10) are in the shape of a circle, a rectangle or a square.

5. The absolute magnetostrictive displacement measuring magnetic tape according to claim 1, characterized in that: The steel wire layer (9), the groove layer (10) and the coating layer (12) are fixed by coupling agent bonding or hot melt bonding.

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